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7c28051e8c
* chore: update toolchain version to 2024-11-05 * update dragon reach to e945c217b3 * update dog to 6f2c0c8f12 --------- Co-authored-by: longjin <longjin@DragonOS.org>
75 lines
2.3 KiB
Rust
75 lines
2.3 KiB
Rust
// Copyright (C) DragonOS Community longjin 2023
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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// Or you can visit https://www.gnu.org/licenses/gpl-2.0.html
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#![allow(dead_code)]
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use core::any::Any;
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use alloc::sync::Arc;
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/// @brief 将Arc<dyn xxx>转换为Arc<具体类型>的trait
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///
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/// 用法：
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///
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/// ```rust
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/// trait Base: Any + Send + Sync + Debug {
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/// fn get_name(&self) -> String;
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/// }
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///
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/// struct A {
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/// name: String,
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/// }
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///
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/// impl DowncastArc for dyn Base {
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/// fn as_any_arc(self: Arc<Self>) -> Arc<dyn Any> {
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/// return self;
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/// }
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/// }
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///
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/// impl Base for A {
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/// fn get_name(&self) -> String {
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/// return self.name.clone();
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/// }
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/// }
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///
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/// fn test() {
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/// let a = A { name: "a".to_string() };
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/// let a_arc: Arc<dyn Base> = Arc::new(a) as Arc<dyn Base>;
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/// let a_arc2: Option<Arc<A>> = a_arc.downcast_arc::<A>();
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/// assert!(a_arc2.is_some());
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/// }
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/// ```
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pub trait DowncastArc: Any + Send + Sync {
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/// 请在具体类型中实现这个函数，返回self
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fn as_any_arc(self: Arc<Self>) -> Arc<dyn Any>;
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/// @brief 将Arc<dyn xxx>转换为Arc<具体类型>
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///
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/// 如果Arc<dyn xxx>是Arc<具体类型>，则返回Some(Arc<具体类型>)，否则返回None
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///
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/// @param self Arc<dyn xxx>
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fn downcast_arc<T: Any + Send + Sync>(self: Arc<Self>) -> Option<Arc<T>> {
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let x: Arc<dyn Any> = self.as_any_arc();
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if x.is::<T>() {
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// into_raw不会改变引用计数
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let p = Arc::into_raw(x);
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let new = unsafe { Arc::from_raw(p as *const T) };
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return Some(new);
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}
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return None;
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}
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}
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